Apt, maybe, for a place associated with men who took a very big gamble and lost it, by going ahead with the 1984/5 pit strike without a ballot of members.

The building did not last long as the NUM's national base in spite of careful architectural detailing including its shape which is based on a miner's pick. The NUM moved there from London in 1988 but then decamped to the old Yorkshire regional office in Barnsley – nick-named King Arthur's Castle, as the industry dwindled and the union's membership likewise.

It was never a happy residence either, with endless planning rows which led to the main entrance never being completed; a strange gap persisted between the pavement in Holly Street and the planned, but unused, front doors.

The city hall and Peace Gardens. Planners think that new use of the old NUM HQ will enliven the central area. Sheffield. Photograph: Alamy

Sheffield's Labour-led city council has approved conversion of the building to house a 38,000 sq ft (3,500 sq m) casino which will be open round the clock. There will also be two restaurants and a rooftop bar. The development ends the city's distinguished claim to be the only one of its size in the UK without a central casino.

There were only seven objection to the plan, all raising the possibility of late-night noise and anti-social behaviour related to drinking. But Andrew Stevens of the developers Brook Leisure says:

We will respect our neighbours. Casinos tend not to be as noisy as some other venues in the city.

The council's planning committee agreed with its officers that renewed life for the building would make:

a significant contribution to the appearance of the building and the wider area.

Work will begin in the conversion in the spring and Brook Leisure says that the project is expected to create about 130 jobs.

PS on a completely different subject: Occupy Leeds are having carols in City Square from around 1.30pm today, Tuesday 20 December. Hope to bring you a post later but they always welcome visitors of all views. And singers...